Process for laser machining continuous metal strip

ABSTRACT

A method for laser machining parts from a strip comprises providing a strip of material from which parts are to be made, feeding the strip into a laser station having first and second lasers, and positioning the first laser with respect to the strip. With the first laser, the method then includes laser machining substantially all of an outline of a plurality of parts in sequence along the strip, leaving at least one tab portion connecting each part to the strip. The second laser is then positioned with respect to the strip and, with the second laser, the method then includes laser machining tab portions connecting parts to the strip in sequence along the strip, and separating the laser machined parts from remaining portions of the strip. Preferably, the first laser and the second laser move simultaneously in the same direction with respect to the strip during laser machining.

This is a continuation-in-part of U.S. Ser. No. 09/548,561, filed onApr. 13, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for lasermachining metal parts from a continuous strip.

2. Description of Related Art

Rotary shavers heads employ shaver cups which contact the user's skinand include slots which permit the hairs on the skin to pass through tobe clipped by the cutters mounted within the cup. The mechanical formingand machining of rotary shaver heads is a labor intensive and costlyprocess since the cups are first drawn by conventional mechanicalforming process into individual parts. The individual parts are thenmounted in further machinery wherein the top portion of the cup whichcontacts the user's skin is lapped, machined or other wise reduced inthickness to provide a relatively thin section. Finally, the cup is thenmounted in another machine where cutting or grinding blades cut thefinely spaced, individual slots in the top cup portion. This multipleprocessing of small parts cannot easily be automated and is costly toperform.

While laser machining to form holes has been known, laser machiningprocesses have generally been done on finished parts (see for exampleU.S. Pat. No. 5,058,413), with attendant handling difficulties. Whilelaser drilling of holes has been performed in steel sheets (e.g., U.S.Pat. No. 5,089,062), this has not generally been known in conjunctionwith mechanical formation of the sheet material.

Bearing in mind the problems and deficiencies of the prior art, it istherefore an object of the present invention to provide an improvedprocess and apparatus to produce rotary shaver heads and other metalparts.

It is another object of the present invention to provide a process andapparatus which eliminates individual handling of rotary shaver andother metal parts during process, where the process requires making fineholes in the parts.

A further object of the invention is to provide an improved machiningprocess and apparatus which provides flexibility in laser machiningindividual parts.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

SUMMARY OF THE INVENTION

The above and other objects, which will be apparent to those skilled inthe art, are provided in the present invention which relates in a firstaspect to a method for making parts from deformable strip comprisingproviding a continuous strip of deformable material, preferablyplastically deformable, from which parts are to be made; mechanicallyforming a plurality of parts in sequence along the strip; lasermachining a plurality of parts in sequence along the strip; andseparating the mechanically formed, laser machined parts from remainingportions of the strip. The laser machining may precede or follow themechanically forming of the parts.

In another aspect, the present invention provides a method for makingparts from strip metal comprising providing a strip of metal from whichparts are to be made; partially mechanically forming a plurality ofparts in a portion of the metal strip; laser machining the partiallymechanically formed parts while in the metal strip; further mechanicallyforming the laser machined, partially mechanically formed parts while inthe metal strip; and separating the further mechanically formed, lasermachined parts from remaining portions of the metal strip. Preferably,the partial and further mechanically forming steps and the lasermachining step include feeding the metal strip into a press to partiallymechanically form the parts. The partial and further mechanicallyforming steps may comprises drawing the parts, and the laser machiningstep may comprise laser etching or laser machining holes in the parts.The method steps are preferably continuously and sequentially performed.The metal strip may be accumulated in an accumulator to control processspeed differences between the partially mechanically forming step andthe laser machining step or between the laser machining step and thefurther mechanically forming step.

In another related aspect, the present invention provides a method formaking parts from strip metal comprising providing a strip of metal fromwhich parts are to be made; providing a first press to partiallymechanically form parts in the metal strip; providing a laser machiningstation to laser machine parts in the metal strip; and providing asecond press to further mechanically form parts in the metal strip. Themethod is then performed by feeding the metal strip into the first pressand partially mechanically forming a plurality of parts in a portion ofthe metal strip; thereafter feeding the metal strip into the lasermachining station and laser machining the partially mechanically formedparts while in the metal strip; feeding the metal strip into the secondpress and further mechanically forming the laser machined, partiallymechanically formed parts while in the metal strip; and separating thefurther mechanically formed, laser machined parts from remainingportions of the metal strip. The metal strip may be provided in coiledform, and the steps following feeding the metal strip into the firstpress are performed without re-coiling the metal strip. The method mayfurther include providing an accumulator between the first press and thelaser machining station and accumulating metal strip in the accumulatorto control process speed differences between the first press and thelaser machining station. The partial mechanical forming step maycomprises partially drawing the parts and the further mechanical formingstep may comprise finish drawing the parts. The laser machining step maycomprise laser etching the parts or laser machining holes in the parts.

In a particularly preferred embodiment, in the first press there arepartially drawn a plurality of shaver cups in a portion of the metalstrip, in the laser machining station there are laser machined slots inthe shaver cups in the metal strip, more preferably curved slots, and inthe second press there are finish drawn a plurality of the shaver cupsin the metal strip.

In yet another aspect, the present invention relates to an apparatus formaking parts from strip metal comprising an uncoiler adapted to uncoil astrip of metal from which parts are to be made; a first press adapted topartially mechanically form a plurality of parts in a portion of themetal strip; a laser machining station adapted to laser machine thepartially mechanically formed parts while in the metal strip; and asecond press adapted to further mechanically form the laser machined,partially mechanically formed parts while in the metal strip.Preferably, the second press is further adapted to separate the furthermechanically formed, laser machined parts from remaining portions of themetal strip. The apparatus preferably includes a metal strip accumulatorbetween the first press and the laser machining station adapted tocontrol process speed differences between the first press and the lasermachining station.

In a further aspect, the present invention provides a method for lasermachining parts from a strip comprising providing a strip of materialfrom which parts are to be made, feeding the strip into a laser stationhaving a laser, and positioning the laser into a first position withrespect to the strip. In the first laser position, the method thenincludes laser machining substantially all of an outline of a pluralityof parts in sequence along the strip, leaving at least one tab portionconnecting each part to the strip. The laser is then positioned into asecond position, different from the first position, with respect to thestrip. In the second laser position, the method then includes lasermachining the tab portions connecting the parts to the strip in sequencealong the strip, and separating the laser machined parts from remainingportions of the strip.

Another aspect of the present invention provides a method for lasermachining parts from a strip comprising providing a strip of materialfrom which parts are to be made, feeding the strip into a laser stationhaving first and second lasers, and positioning the first laser withrespect to the strip. With the first laser, the method then includeslaser machining substantially all of an outline of a plurality of partsin sequence along the strip, leaving at least one tab portion connectingeach part to the strip. The second laser is then positioned with respectto the strip and, with the second laser, the method then includes lasermachining tab portions connecting parts to the strip in sequence alongthe strip, and separating the laser machined parts from remainingportions of the strip. Preferably, the first laser and the second lasermove simultaneously in the same direction with respect to the stripduring laser machining.

Yet another aspect of the present invention provides a method for lasermachining parts from a strip comprising providing a strip of materialfrom which parts are to be made, feeding the strip into a first laserstation and, in the first laser station, laser machining substantiallyall of an outline of a plurality of parts in sequence along the strip,leaving at least one tab portion connecting each part to the strip. Themethod then includes feeding the strip into a second laser station, and,in the second laser station, laser machining the tab portions connectingthe parts to the strip in sequence along the strip, and thereafterseparating the laser machined parts from remaining portions of thestrip.

The present invention also provides a method for making parts from stripmetal comprising providing a strip of metal from which parts are to bemade, mechanically forming pilot holes in the metal strip, and feedingthe strip into one or more laser stations. In the one or more laserstations, the method then includes laser machining a plurality of partsin sequence along the strip, leaving at least one tab portion connectingeach part to the strip and separating the laser machined parts fromremaining portions of the strip.

In all of the aforestated methods, the strip preferably comprises acontinuous strip initially in coil form. A servo-controlled feeder maybe connected to the laser station to receive and feed the strip in adesired position relative to the laser. Such servo-controlled feeder mayinclude a pilot pin that is adapted to engage a hole in the strip toposition the strip in a desired position during laser machining, and todisengage from the strip hole during strip feeding.

In related aspects, the present invention further provides an apparatusfor making parts from strip metal comprising an uncoiler adapted touncoil a strip of metal from which parts are to be made, and a firstpress adapted to form sequential pilot holes in a portion of the metalstrip. The apparatus further includes a first laser adapted to lasermachine substantially all of an outline of a plurality of parts insequence along the strip, leaving at least one tab portion connectingeach part to the strip and a second laser, following the first laser,adapted to laser machine the tab portions connecting the parts to thestrip in sequence along the strip, thereby causing the laser machinedparts to separate from remaining portions of the strip.

Preferably, there are provided metal strip accumulators between thefirst press and the first and second lasers adapted to control processspeed differences between the first press and the first and second lasermachining stations. Also, the first laser and the second laser arepreferably adapted to move simultaneously in the same direction withrespect to the strip during laser machining. The first laser and thesecond laser may be disposed in separate laser stations, or they mayboth be disposed in a single laser station. A fiber optic cable maytransmit laser light from a laser power supply to the one or more lasersor laser heads.

A further aspect of the present invention provides an apparatus formaking parts from strip metal comprising a laser machining stationhaving at least one laser head to laser machine a plurality of parts insequence along a strip and a servo-controlled feeder connected to thelaser machining station to receive and feed the strip in a desiredposition relative to the at least one laser head. In a preferredembodiment the servo-controlled feeder includes a pilot pin that isadapted to engage a hole in the strip to position the strip in a desiredposition during laser machining, and to disengage from the strip holeduring strip feeding.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elementscharacteristic of the invention are set forth with particularity in theappended claims. The figures are for illustration purposes only and arenot drawn to scale. The invention itself, however, both as toorganization and method of operation, may best be understood byreference to the detailed description which follows taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a top plan view of a continuous strip of metal or otherformable material showing the progressive sequence of part formation inthe strip prior to laser machining.

FIG. 2 is a top plan view of the continuous strip of metal or otherformable material of FIG. 1 showing the progressive sequence of partformation in the strip subsequent to laser machining.

FIG. 3a is a top plan view of a first stage of a part formed in a stripin accordance with one embodiment of the present invention.

FIG. 3b is a side elevational view of the part shown in FIG. 3a.

FIG. 4a is a top plan view of a second stage of a part formed in a stripin accordance with one embodiment of the present invention.

FIG. 4b is a side elevational view of the part shown along line 4 b-4 bin FIG. 4a.

FIG. 5a is a top plan view of a third stage of a part formed in a stripin accordance with one embodiment of the present invention.

FIG. 5b is a side elevational view of the part shown along line 5 b-5 bin FIG. 5a.

FIG. 6a is a top plan view of a fourth stage of a part formed in a stripin accordance with one embodiment of the present invention.

FIG. 6b is a side elevational view of the part shown along line 6 b-6 bin FIG. 6a.

FIG. 7a is a top plan view of a fifth stage of a part formed in a stripin accordance with one embodiment of the present invention.

FIG. 7b is a side elevational view of the part shown along line 7 b-7 bin FIG. 7a.

FIG. 8a is a top plan view of a sixth stage of a part formed from astrip in accordance with one embodiment of the present invention.

FIG. 8b is a side elevational view of the part shown along line 8 b-8 bin FIG. 8a.

FIG. 9 is a side view, partially in schematic, of a first preferredprocess in accordance with the embodiment of the present inventiondepicted in FIGS. 1-8b.

FIG. 10 is a side view of an embodiment of the present inventionemploying laser etching.

FIG. 11 is a side view, partially in schematic, of another preferredprocess in accordance with the embodiment of the present invention.

FIG. 12 is a perspective view of a feeder station shown in FIGS. 9 and11.

FIG. 13 is an exploded perspective view of the laser stations in FIGS. 9and 11.

FIG. 14 is a perspective view of a strip being laser machined in thefirst laser station of FIG. 11.

FIG. 15 is a top plan view of a partial laser machined part retained inthe strip after the first laser station of FIG. 11.

FIG. 16 is a top plan view of the final laser machined part as separatedfrom the strip after the second laser station of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing the preferred embodiment of the present invention,reference will be made herein to FIGS. 1-16 of the drawings in whichlike numerals refer to like features of the invention. Features of theinvention are not necessarily shown to scale in the drawings.

In general, the present invention is directed to a process and apparatusfor laser machining formed strip metal into parts which are processed incontinuous strip form, and then are separated into individual parts onlyat the end of mechanical and laser forming and machining. In particular,the process of the present invention has been found to be especiallyuseful for producing rotary shaver cups or like items. The presentinvention creates a more robust rotary shaver by enhancing the closenessof the cut and the opportunity of the rotary shaver blades to cut. Thecloseness of cut is controlled by the thickness of the top portion ofthe shaver cup, i.e., the distance from the skin surface to the apex ofthe cutting element in its centrifugal runout. The opportunity to cut isthe active perimeter that is available for cutting along the outercircumference of the shaver cup. The more openings there are in the cup,the faster the cup can collect hairs for cutting by the cutters. If therotary cutter and shaver cup are not in proper engagement, the whiskerhair can push the cutter down or away from the cut. Moreover, the rotaryshaver cup of the present invention better directs hairs to uncurl andstraighten out as they are being cut.

As broadly defined, the process generally comprises feeding a strip ofmetal into an otherwise conventional press and partially, mechanicallyforming a part in the strip, without removing the part from the strip.The partially formed part, as still attached to the strip, is then fedcontinuously into a laser machining station where a laser then performsthe desired machining to the part while attached to the strip.Alternatively, the process as broadly defined utilizes successive laserstations to machine a desired part from the strip, preferably afterforming pilot holes in the strip, more preferably after mechanicallyforming those holes. As used herein, the term laser machining refers toa hole cutting, etching (e.g., partial cutting through a thickness) orother conventional laser machining processes. The laser machining mayalso precede the mechanical forming. Preferably, the partially formed,laser machined part, again as it is still attached to the strip, is thenfed into another press and the mechanical part formation is finishedand/or the part is cut out and separated from the strip.

The process of the present invention used to form the preferred rotaryshaver head is depicted in FIGS. 1-8b. Overall views of the strip beforeand after laser machining are shown in FIGS. 1 and 2, respectively,while individual part formation views are shown in FIGS. 2a-8 b. Thesequential locations of part formation views 2 a-8 a on the strip areindicated on FIGS. 1 and 2. An overall process apparatus schematic forthis embodiment as well as other embodiments is depicted in FIG. 9.Initially, a strip 22 of sheet metal or other formable material isobtained in coil form 20 for feeding into a first press 30 wherein thepart is to be partially mechanically formed while still attached tostrip 22. The strip used to form the rotary shaver cup in particular ispreferably annealed medium carbon steel, although the process of thepresent invention may be used in general with low, medium or high carbonsteel, or other metals and alloys in strip form. In the process, thecoil of strip steel from which the part is to be made is first loadedinto a payoff reel 21 and made ready to enter the feed in the firstpress. The feeder 23 a, which precedes the first die, precisely sets thelead or progression of the strip as it travels through the die. Afterentering the first progressive die, registration or pilot holes 27, foradvancing the strip through the die, and part central holes 28 creatingthe inner diameter shape are pierced in strip 22 in the first station.In a manner well known in the prior art, two parts are formed along thewidth of strip 22, with one part advanced with respect to the other byone-half the part pitch, for efficient utilization of the strip. Whilepart formation views 3 a-8 a are indicated with respect to the parts onthe left hand portion of the strips shown in FIGS. 1 and 2, it is to beunderstood that the same operations are made to the parts on the righthand portion of the strip.

In the second die station the portion 29 of the strip around centralhole 28 is thinned from its original strip thickness by cold reducing orhammering. This thickness reduction in area 29 is desirable for thecentral portion of the finished part which eventually forms the slottedcomb portion of the shaver head, and will be omitted from subsequentviews for clarity of other operations.

In the case of the rotary shaver head, the next die station in press 30makes partial lance cuts 25 a to substantially form flat blank 24 whileuncut sections 26 a retain blank 24 in strip 22 (FIGS. 1, 3 a and 3 b).Additional lance cuts 25 b with uncut sections 26 b rotated 90° fromuncut sections 26 a are then formed (FIG. 1), so that part blank 24remains connected to strip 22. In the second operation on part blank 24,a subsequent die station in press 30 draws a central concave depression27 downward (FIGS. 1, 4 a and 4 b). Additional lanced cuts 25c againrotated 90° are added outside cuts 25 b, leaving uncut sections 26 c.The partially mechanically formed part 24 begins to shrink in diameterbut still remains connected to strip 22 by a connecting web formed bylanced cuts 25 a, 25 b, 25c and uncut sections 26 a, 26 b, 26 c. Thisconnecting web remains to connect the partially formed part to strip 22throughout the processing until the final die station in the secondpress, as discussed further below. In the next die station in press 30,a second draw upward creates what will be the top outer form 31 ofrotary shaver part 24 (FIGS. 1, 5 a and 5 b). It is to be understoodthat the part forming operations described above are progressive andsequential.

The continuous strip of partially formed parts then leaves the firstpress, travels through a delay loop in accumulator 35 a and then entersa second feeder 23 b before entering a multi-head laser machiningstation 40. The laser is capable of creating a burr free through holeand with precise geometry and tight slot width by controlling the widthof the laser beam. The laser obtains its orientation to the cup fromregistration holes 27 in the strip to which the cup is attached. Thelaser machining station may have as many laser beam emitting heads asneeded coupled in series to create repetitive cutting depending on thenumber of cups in the strip progression. As the series of parts 24 andstrip 22 is fed into laser station 40, a laser beam performs the desiredmachining operation. In the case of the rotary shaver head, the lasercuts a series of slots in thinned section 29 to create a series of slots32, 34 (FIGS. 6a, 6 b). Slots 32 extend radially outward in a somewhatcurved fashion along an inner annular portion of part 24 while slots 34also extend outward in a similarly curved fashion, in the same directionas slots 32, in an outer annular portion of part 24. These slots 32, 34permit the hairs on the user's skin to pass through the shaver cup andbe cut by a cutting blade mounted within the cup. The remaining metalportions between these slots create the stationary counterblades againstwhich the rotary cutting blade pinches and trims the hairs. This slottedportion of the shaver head is also called the comb portion.

The curved, non-linear slots which create the curved comb portionpermits improved cutting geometry of the shaver head. The clockwisecircular pattern of comb slots enhances whisker entry into the cut zoneand permits tall or standing curled whisker hairs into the screen cup.The actual slot width is not dictated by any particular cutting sawparameters as in the prior art, but simply by the width and thermalcolumn of the laser beam, thereby creating any size comb slot needed forany beard condition.

After exiting the laser station, the strip and partially laser machinedformed parts enters a second delay loop accumulator 35 b and feeder 23 cprior to entering the second press 50 (FIG. 9). Both the first andsecond delay loops 35 a, 35 b and feeders 23 a, 23 b, 23 c are useful tocorrect small irregularities in feed timing to ensure continuousfunction of presses 30 and 50 and laser station 40. Computer 60 isconnected to and controls all of the machining stations 30, 40, 50,accumulators 35 a, 35 b and feeders 23 a, 23 b, 23 c, and any othermechanical systems used in processing the present invention. Strip parts24, which are still connected by webs created by partial lanced cuts 25a, 25 b and uncut edges 26 a, 26 b to strip 22, are then fed in acontrolled manner into second mechanical press 50 for finished forming.In the case of the rotary shaver head, this finish forming comprises oneor more die stations in press 50 which continues the drawing of the part24 to a deeper draw, without interfering or reforming the portions ofthe cup which have been laser machined. The series of draw stationsestablishes the final elevation and outer diameter of the cup. Duringthese draw stations the die system first engages the existing lasermachined comb portion below the demarcation area of the first draw. Bycapturing the first draw comb portion before the second draw station isengaged, the comb portion of the cup is securely isolated from anydistortion. A double bend 33 is created at the periphery of part 24 tocreate additional hoop strength or stiffening to the part (FIGS. 2, 7 aand 7 b). The cup is then drawn to its final elevation and is carried toa pinch trim station where it is blanked through the die and severedfrom the strip becoming a separate piece 36 (FIGS. 2, 8 a and 8 b). Theremaining strip 22, minus the formed parts, continues to a scrap chopperwhich creates the scrap strip 38 which is ejected from the press andthen removed for proper disposal.

The finished formed rotary shaver cup 36 may then be further processedas desired. Although prior to the first draw stations in press 30 theportion of the part which forms the actual comb face was described asbeing cold formed or hammered to reduce its thickness by 50% or more,alternatively a lapping operation may be performed to reduce thethickness of the cut comb section of the shaver. For example, rotarylapping of the cup face may decrease the thickness of the strip from aninitial thickness of 0.008 inches to a final thickness of 0.0032-0.0046inches. Once the comb portion of the separated part is at the desiredthickness, part 36 may then be pressure washed and a nickel platingapplied, for example, with a thickness of 0.006 inches.

In processing other parts, instead of through cutting by the lasermachining process, the process of the present invention may utilize anengraving laser machining process to mark additional features on theproduct. This laser engraving may be used with or without other lasermachining for other parts for example identification plates. This may beaccomplished as shown in FIG. 10 by starting with a strip 70, such asaluminum or steel, which may be supplied in coil form and continuouslycoated with a plurality of different color paints or coatings, such asthree sequential layers 74, 76, 78. A first press includes one or moredies for piercing holes and forming a border bead 72 in the coated strip70. The strip then enters the laser station where a laser beam etches orburns through the coating layers to different depths to expose differentcolor layers, for example, two layer etching 80 to expose color layer 74or single layer etching 82 to expose different color layer 76. In thismanner desired characters or symbols of colors 74 and 76 are created oncolor background 78. By employing laser etching speeds of up to 1000in./min. or more and variable laser beam widths created by multiplelaser heads, the laser machining station will be able to keep up withthe high speed mechanical forming operations. A subsequent press wouldthen cut the finished part from the strip along edge 84.

A further embodiment for laser machining strip, in continuous coil formor in discrete sheets or pieces, is depicted in FIGS. 11-16.

In a schematic view depicted in FIG. 11, which is similar to that shownin FIG. 9, the first machining station 30 comprises a pilot hole cuttingstation, preferably utilizing a press to mechanically form the pilothole. First laser station 40 a preferably is the primary laser cuttingstation, and there is further provided a second laser cutting station 40b. In each laser station there are provided one, two or more laser headscontaining lasers to cut or otherwise machine strip 122 as it travelsdownstream of the first press 30. Feeder stations 23 b, 23 c areassociated with laser stations 40 a, 40 b, respectively. The remainingapparatus is as described in connection with FIG. 9.

As depicted in FIG. 12, feeder stations 23 b, 23 c preferably include apair of guide rails 110 a, 110 b which each have a guide slot or notch111 which receives the edges of strip 122. Pilot holes 127 have beenpreviously formed in strip 122, preferably in first press 30 by theprocess previously described. A pilot air cylinder body 116 with airinlets and outlets for connection to a source of pressurized air ismounted on a pilot guide block 114, which extends outward over the stripin the y-direction and is slidable longitudinally in the x-direction ofthe strip in guide track 112 at the top of guide rail 110 a. Extendingfrom below pilot cylinder 116 is pilot pin 118 which moves upward anddownward in the z-direction and is configured to be received withinstrip pilot holes 127 in sequential fashion. Initially, the strip willtypically be manually threaded into and through guide slots 111 and intofeeder assembly 23 b or 23 c. A signal is then sent to themicroprocessor-based controller (PC) and the pilot pin is retracted inan up position into the cylinder and disengaged out of the strip holes,which is then signaled to the PC. The servo-controlled feeder feeds thestrip a specified length equal to a multiple of the pilot hole 127distance or pitch and sends a signal to the PC, whereupon pilot pin 118is brought down and engaged within a particular pilot hole 127. The tipof pilot pin 118 is tapered so that if there is a minor mis-registrationbetween the pin and the pilot hole, the entry of the tapered segmentwithin the pilot hole will cause the strip to shift to the correctposition. Once the pilot pin is moved down within the pilot hole, thestrip is locked and a signal is sent to the PC, which then initiates thelaser machining. The position of the pilot pin within the cylinder bodyis determined by a magnetic sensor read switch, which generates therespective engaged and disengaged position signals. At the end of theparticular laser machining step, the pilot pin moves upward, the signalis sent to the PC and the servo feeds the strip a specific feed length,whereupon the process begins again.

Laser machining stations 40 a, 40 b, are depicted in exploded view inFIG. 13 and receiving the strip 122 in FIG. 14. The feeder stations 23b, 23 c may be connected to the respective laser machining stations 48a, 40 b by mounting plate 128. Each laser machining station includes anopen rectangular frame 130 which receives a work platform 132 which ismade up of a plurality of pointed supporting teeth 134 which support thesheet at individual, mutually spaced points. This permits through-lasercutting with a minimum of disruption to the work platform. Of course, atsome point the work platform will become excessively damaged by suchthrough-laser machining and will have to be replaced. This is easilydone by removing securing brackets 130 a, 130 b which secure the workplatform 132 to the frame 130. In the case of laser machining thinstrip, tandem servos, e.g. two feeders, may maintain tension on eitherside of the laser machining station during the laser machining process.

In order to support the sheet of material in a longitudinal direction,there is provided an outrigger holding arm assembly 136 a whichcomprises members 138 extending in the y-direction connected by members140 extending in the x-direction and secured by brackets to frame 130.This extends the effective support length of frame 130. If individual,discontinuous sheets of width wider than the feeder are cut using thelaser-machining station 40 a, 40 b, a further side outrigger assembly136 b may be employed utilizing members 138 extending in the x-directionconnected by members 140 extending in the y-direction and connected bybrackets to frame 130. A pair of laser heads 115 a, 115 b (FIG. 14) aresuspended over the laser machining frame 130 and strip by supporting arm148, which also connects to frame 130. A yttrium/aluminum/garnet (YAG)or other suitable laser is contained in laser power supply 151, anddelivers the laser light through fiber optic cable 117 to laser heads115 a, b. A microprocessor based x-y controller, which may be containedin computer 60 (FIG. 11), controls and directs movement of the laserheads and arm over strip 122 in the desired pattern to laser machine theparts.

As shown in FIG. 14 and FIG. 15, a first laser station may make apartial laser machining of a part 150 which extensively cuts orotherwise laser machines the part, but still permits the part to beretained within and held by the remainder of strip 122. In particular,finished laser cuts 152 extend around the inner and outer peripheries ofthe part 150 except at tab sections 154 which remain uncut and providethe connection to and support by the remainder of strip 122. In a secondlaser machining station 140 b, the laser machining may be completed bycutting tabs 154 along the outer and inner periphery of part 150,resulting in a final part configuration (FIG. 16) which is separatedfrom the remainder of strip 122 and consists entirely of laser-cutopenings and edges. Alternatively, some openings or edges on the partmay be press formed or cut by first press 30. A conventional knock outarm (not shown) may assist in dropping or otherwise separating part 150from the remainder of strip 122. The remainder of strip 122 may be thendiscarded to scrap while the finished parts 150 are stored (FIG. 11).

Instead of using separate laser machining stations as shown in FIG. 11,the present invention may employ a single laser machining station havingone, two or more laser heads for laser machining the strip. In the caseof only one laser head, the strip into the laser station and the laseris brought into a first position with respect to the strip. In the firstposition, the laser machines substantially all of the outline of theparts in sequence along the strip, leaving at least one tab portionconnecting each part to the strip. The laser is then brought into adifferent, second position, downstream or further along the strip, whereit laser machines the tab portions connecting the parts to the strip insequence along the strip, thereby separating the laser machined partsfrom remaining portions of the strip.

Where two or more lasers are used in the same laser station, the lasersmay move simultaneously in the same direction with respect to the strip,but each over different portions of the strip, during the lasermachining. For example, a first laser will laser machine fresh strip tocreate substantially all of the outline of the parts, leaving at leastone tab portion connecting each part to the strip, while a second laserwill laser machine the tab portions connecting the parts to the strip toseparate the parts from the strip. The same x-y controller directs andcontrol both lasers. At the conclusion of the machining operation byeach laser, the strip feeder advances the strip so that the partiallaser machining created by the first laser (FIG. 15) is below the secondlaser, and fresh strip is below the first laser. The cycle is thenrepeated.

The present invention may be integrated with existing manufacturingsystems which utilize one or more die stations to mechanically form apart, before, after, or both before and after, the laser machiningstage. Alternatively, the present invention utilizes one or moresuccessive laser stations to machine a desired part from the strip,preferably after mechanically forming pilot holes in the strip. Theprocess is achieved in continuous strip format resulting in progressivepart manufacturing that has considerable advantages over individual parthandling used prior for laser machining parts.

While the present invention has been particularly described, inconjunction with a specific preferred embodiment, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description. It istherefore contemplated that the appended claims will embrace any suchalternatives, modifications and variations as falling within the truescope and spirit of the present invention.

Thus, having described the invention, what is claimed is:
 1. A methodfor laser machining parts from a strip comprising: providing a strip ofmaterial from which parts are to be made; feeding the strip into a laserstation having a laser; positioning the laser into a first position withrespect to the strip; in the first laser position, laser machiningsubstantially all of an outline of a plurality of parts in sequencealong the strip, leaving at least one tab portion connecting each partto the strip; positioning the laser into a second position, differentfrom the first position, with respect to the strip; in the second laserposition, laser machining the tab portions connecting the parts to thestrip in sequence along the strip; and separating the laser machinedparts from remaining portions of the strip.
 2. The method of claim 1wherein the strip comprises a continuous strip initially in coil form.3. The method of claim 1 further including a servo-controlled feederconnected to the laser station to receive and feed the strip in adesired position relative to the laser.
 4. The method of claim 3 whereinthe servo-controlled feeder includes a pilot pin that is adapted toengage a hole in the strip to position the strip in a desired positionduring laser machining, and to disengage from the strip hole duringstrip feeding.
 5. A method for laser machining parts from a stripcomprising: providing a strip of material from which parts are to bemade; feeding the strip into a laser station having first and secondlasers; positioning the first laser with respect to the strip; with thefirst laser, laser machining substantially all of an outline of aplurality of parts in sequence along the strip, leaving at least one tabportion connecting each part to the strip; positioning the second laserwith respect to the strip; with the second laser, laser machining tabportions connecting parts to the strip in sequence along the strip; andseparating the laser machined parts from remaining portions of thestrip.
 6. The method of claim 5 wherein the first laser and the secondlaser move simultaneously in the same direction with respect to thestrip during laser machining.
 7. The method of claim 5 wherein the stripcomprises a continuous strip initially in coil form.
 8. The method ofclaim 5 further including a servo-controlled feeder connected to thelaser station to receive and feed the strip in a desired positionrelative to the first and second lasers.
 9. The method of claim 8wherein the servo-controlled feeder includes a pilot pin that is adaptedto engage a hole in the strip to position the strip in a desiredposition during laser machining, and to disengage from the strip holeduring strip feeding.
 10. A method for laser machining parts from astrip comprising: providing a strip of material from which parts are tobe made; feeding the strip into a first laser station; in the firstlaser station, laser machining substantially all of an outline of aplurality of parts in sequence along the strip, leaving at least one tabportion connecting each part to the strip; feeding the strip into asecond laser station; in the second laser station, laser machining thetab portions connecting the parts to the strip in sequence along thestrip; and separating the laser machined parts from remaining portionsof the strip.
 11. The method of claim 10 wherein the strip comprises acontinuous strip initially in coil form.
 12. A method for making partsfrom strip metal comprising: providing a strip of metal from which partsare to be made; mechanically forming pilot holes in the metal strip;feeding the strip into one or more laser stations; in the one or morelaser stations, laser machining a plurality of parts in sequence alongthe strip, leaving at least one tab portion connecting each part to thestrip; separating the laser machined parts from remaining portions ofthe strip.
 13. The method of claim 12 wherein the strip comprises acontinuous strip initially in coil form.
 14. A process for making partsfrom a deformable strip comprising: providing a continuous strip ofdeformable material from which a plurality of parts are to be made;mechanically forming the plurality of parts in sequence along the strip;laser machining the plurality of parts in sequence along the strip; andseparating the mechanically formed, laser machined parts from remainingportions of the strip.
 15. The method of claim 14 wherein themechanically forming precedes the laser machining of the parts.
 16. Themethod of claim 14 wherein the laser machining precedes the mechanicallyforming of the parts.